An Early View
Back to the original question: When does a project actually start? This inquiry might be interpreted as "When does a project really start", I mean really get going?" And that could only be when a formal command is given and significant effort is poured into the project, such as upon the signing of a contract for construction in that particular industry.
Indeed, this was a popular view before the days of the Project Management Institute's original PMBOK 1987 document mentioned previously. In those days, academia's view was that a project was only a Project when a contract was signed for the commencement of some serious infrastructure, and then only when digging was commenced for the foundations. Of course a lot of work had to be done before that, such as development of product concepts, planning, financing, concept and then detailed design drawings, estimating, procurement, and so on. But somehow that was not seen as a part of The Project, because it was not included in the regular contractor's construction contract.
Today, our view is much broader and covers a much wider spectrum of projects. But even so, there must still be some dedicated effort put into preparation and early decision-making. All of which is why I have put the question: When does a project actually start?
I want to get back to the real beginning, that is, the instant before which there was no mention of a particular project, and after which there clearly was evidence of a project. In other words, the very first time when some recorded effort has been applied towards some specific project goal.
Surely such an event is the real starting point of the Project Life Span?
3. Or Project Life Cycle if you prefer.